In contrast to the above studies, which reported positive associations, Australian researchers evaluated healthy individuals for H. pylori infection, MBL2 genotype, mannan binding level, and complement 4 level in plasma, and found that MBL deficiency, defined by either genotype or plasma activity, was not associated with higher susceptibility to H. pylori infection [33]. The gene discussed is MBL2; the disease is hyperinsulinemic hypoglycemia, familial, 4.